The present invention relates to a semiconductor device. For example, the invention is preferably used for a semiconductor device including nitride semiconductor.
The nitride semiconductor such as gallium nitride (GaN) has a wide bandgap and a high electron mobility compared with silicon (Si) or gallium arsenide (GaAs). Hence, such nitride semiconductor will be promisingly used in high-voltage, high-power, or high-frequency transistors. Hence, there is now developed a power-control field effect transistor (FET) including the nitride semiconductor such as gallium nitride, i.e., a power device.
A semiconductor device including such a field effect transistor desirably includes a protection diode for protecting the field effect transistor so that the field effect transistor is prevented from being broken even if an excessive voltage is applied thereto.
Japanese Unexamined Patent Application Publication No. 2013-16627 (Patent Document 1) describes a technique on a semiconductor device including a semiconductor substrate having a silicon substrate and an npn bipolar transistor including a diffusion layer of an n-type impurity provided in the silicon substrate, and a hetero-junction transistor composed of nitride semiconductor provided on the semiconductor substrate.
Japanese Unexamined Patent Application Publication No. 2009-9993 (Patent Document 2) describes a technique on a semiconductor device in which a heterojunction field effect transistor (HFET) is provided on a silicon pin diode while being integrated with the silicon pin diode.
Japanese Unexamined Patent Application Publication No. 2002-9253 (Patent Document 3) describes a technique on a semiconductor device in which a heterojunction field effect transistor and a protection diode are monolithically provided on a substrate composed of gallium arsenide (GaAs).
Japanese Unexamined Patent Application Publication No. 2008-124421 (Patent Document 4) describes a technique on a semiconductor device including a horizontal insulated gate bipolar transistor (IGBT) provided on a semiconductor substrate.